Tuesday, 3 April 2012

Overview

You’re now on the third and final leg of your journey to understanding desktop
virtualization. This is where you can get information that can help you
decide whether desktop virtualization is right for your organization.
Let’s start off by talking about desktop virtualization challenges. What are
the critics saying? What are the main arguments against
DV?

Arguments against Desktop VirtualizationEach form of Desktop Virtualization has its set of criticisms, and these are
illustrated in the figure below.Arguments against VDIToo complex and costly - These are what most of the VDI critics are
saying; that it’s just way too complex to set up and manage. They say it’s too
costly to acquire, and that you don’t realise any savings at all.Availability and performance is heavily dependent on the network -
Because the VMs are installed on a server in the data center, people don’t see
any offline use case for VDI. And because a connection to the VM is needed, even
if a user is online but the network is slow, performance is expected to
suffer.Storage requirements are too high - When people look at desktop
virtualization, they usually liken it to server virtualization. When treated
this way, VDI’s storage consumption can be staggering. For example, if you have
a thousand users and assign each desktop to a vdisk equivalent to 40 GB, then
you’ll certainly need a lot of storage space.Requires new rounds of training - It introduces a different system
than what people are used to, so users will have to undergo a series of
trainings to be acquainted with it.

Arguments against Terminal ServerLimited personalization features - Users are not given enough
flexibility to customize the desktop in order to suit their personal aesthetic
or functional preferences.Availability and performance is heavily dependent on the network -
Like VDI, Terminal Server is highly reliant on the availability and performance
of the network. If the network is slow or, worse, if it is down, then users
suffer.Limited resource management flexibility - For instance, if you have
300 sessions connecting to a terminal server, then all sessions are forced to
use the same amount of resources. If say, 20 of those sessions need more memory
than the rest, you won’t be able to give them that.Arguments against Application VirtualizationToo complex - Packaging an application entails starting a recording,
storing the application, stopping the recording, and compiling everything
together, which is actually more complicated than a regular application
installation. Updating can also be difficult because when you need to update the
runtime, you will have to compile again.Compatibility and Interoperability issues - Some applications can’t
run on certain operating systems when virtualized, while other applications
simply can’t be virtualized at all.

Arguments against Client HypervisorsUnproven technology - As the newest among this bunch of desktop
virtualization platforms, not many people can vouch for it.Compatibility - Not all existing physical machines can support
client hypervisors. Citrix XenClient, for instance, requires an Intel vPro
processor in order to perform as expected.Requires a PC and physical device management - Remember that you
still need to interact with a physical device to install and manage client
hypervisors.Low performance - This criticism is particularly aimed at Type-2
client hypervisors.

Pointing out the misconceptions
Many of the arguments given in the previous section are actually
misconceptions. Thus, before you make your final judgement on DV, it would only
be fair to weed out those misconceptions first.Cost savings are in OpEx, not in CapEx
When critics say that desktop virtualization solutions are very costly and
that you can’t realize any cost savings, that’s because they’re looking for
CapEx savings. According to research companies like Gartner, IDC, and Forrester
savings from DV actually come from OpEx. Here are some numbers:
So not only do your operational costs go down, so do your hardware/software
costs and your worker downtime. An affected end user can quickly get back up and
running especially if you simply decide to change the hardware. You can’t simply
change the hardware in a traditional desktop scenario.
In addition, because your IT staff no longer have to spend as much time for
on-site troubleshooting and because issues in desktop virtualization-enabled
environments can be remedied much faster, your IT staff productivity levels go
up.
Here’s another illustration supporting OpEx savings in DV:
Thus, it really makes sense to go after savings on the bigger chunk of
expenses, which is OpEx.

Traditional desktop environments are actually more
complexWhen people say that desktop virtualization environments are
complex, they seem to have forgotten how complex traditional desktop
environments are. You have to enforce very strict antivirus policies, you need
to have a system center of configuration manager to effectively manage your
physical machines, you need to employ asset management tools, and so on.
The reason why we think traditional desktops are easier to manage is because
we’ve already gotten used to all the complexities associated with them. But if
we put those complexities side by side with the complexities associated with
desktop virtualization and judge them from a zero-based standpoint, you’ll
realize that traditional desktop environments are actually way more complex
after all.Storage costs are not as high as you think
As mentioned earlier in this article, when people look at the storage costs
of desktop virtualization, they usually treat it like server virtualization
storage costs. When treated this way, VDI’s storage consumption can of course be
staggering. The question is, if you have a thousand users, do you really need
to assign each desktop to a vdisk equivalent to 40 GB?
The answer is “no”. Later on, in the Tips and Best Practices section, we’ll
discuss how you should manage your storage resources so as to keep the costs
affordable.“No offline use-case” is no longer true
Today, with solutions like XenApp or application virtualization, it is now
possible to run applications even when they’re not connected to the server.Heavily reliant on the network - So what business isn’t
nowadays?
If you really think about it, all businesses are now heavily reliant on an
‘up’ network.
You need email or Instant Messaging apps to communicate with colleagues,
suppliers and customers. You need the Internet for anytime/anywhere
collaboration with team members through tools like Microsoft Sharepoint and
Exchange, IBM Lotus Notes and Domino, Adobe Acrobat Connet, Basecamp, and
others.
If you’re an isolated business with no connection to the outside world, then
you can’t hope to compete in today’s heavily connected business environment.
Thus, the argument of desktop virtualization’s heavy reliance on the network is
totally irrelevant.Training?
Training is part and parcel of any productive, innovative, creative
organization. If think you’d like your business to espouse those traits, then
this too, is irrelevant.Operational benefits of DV
Let’s now put together the operational benefits of desktop virtualization
(remember, its main benefit lies in OpEx), some of which have already been
covered earlier in the article.

Faster provisioning - Fast provisioning is very crucial especially
for growing businesses. With DV, you can help new employees hit the ground
running at day one because you can immediately equip them with desktops
faster.

Now supports offline use cases - This has been covered earlier.

Security - ditto

Improves user experience - With platforms like VDI or application
virtualization, you can now enable users to personalize their desktops; a
capability that used to be non-existent with older DV platforms like terminal
server.

Maximizes storage space - Imagine having 500 GB of disk space on
every user’s PC in a traditional desktop environment. Will all of that space be
utilized? No. With DV, you can eliminate under-utilized storage space by moving
storage into the data center and take advantage of dynamic provisioning or thin
provisioning.

Enables better performance

Many applications will run faster if you put them on a data center, on top
of datacenter-class hardware.

In a VDI or Terminal Server model, it is only screen updates that are being
sent to the user. So, you can actually use video rendering apps and graphics
intensive apps like Photoshop, Autocad, or Sony Vegas on them.

In addition, you can use those apps over a WAN. For example, you can employ
Citrix’s HDX technology to deliver a high-definition desktop virtualization user
experience to end users over the network.

Tips and best practices

Just like any technology, the benefits of desktop virtualization can only be
realized if you use it properly. In this section, we’ll discuss some tips and
best practices so you’ll know how to get the most out of a DV environment.Get out of the server virtualization mindset when you deal with
DV
Again, desktop virtualization should be treated differently. One way to deal
with storage problems is to employ thin provisioning and image management. Thin
provisioning limits allocation for your initial storage. Thus, you don’t have to
use full storage capabilities right away.Understand where the value of DV lies
Always remember that OpEx is where you’ll see huge savings in DV. DV will
also help you in improving resource utilization through efficient management. By
bearing these in mind, you’ll be able to effectively leverage DV’s strengths to
your advantage.Integrate DV into the overall desktop management
strategy
Chances are, you won’t be able to make a complete migration from physical to
virtual in just one go, so you can expect to initially have a hybrid of physical
and virtual desktops. You must therefore be able to integrate the DVs into your
overall desktop management strategy.
Here are some steps you can take on your way to a complete migration to
desktop virtualization:

Identify where your existing infrastructure’s costs are and determine
whether there is a case to deliver an ROI

Formulate solid business cases that DV can address.

Identify both the limitations and the business values of DV

Evaluate vendors and their solutions to determine which of them can
provide the best fit

Conduct a Proof of Concept (POC) and pilot to gauge the ideal product
and user fit

Deploy your chosen DV solutions to a selected group of users then
evaluate. If that is successful, move on to a stage deployment. If that works as
well, scale up accordingly.

Citrix XenDesktop 5 - More than just an end-to-end desktop
virtualization solution

Remember that there are different groups of desktop users and there are
specific DV platforms that are best suited for each particular group. In other
words, there’s no such thing as a one-size-fits-all DV solution. However, there
exists an end-to-end desktop virtualization solution that can support all the
major forms of DV. It’s Citrix’s XenDesktop.
Citrix XenDesktop can support VDI, Application Virtualization, Streaming,
Terminal Server, and Type-1 Client Hypervisor. Thus, in XenDesktop, you have one
DV product that can cater to the entire spectrum of users.
XenDesktop relies on a very robust remote protocol known as IMA or HDX. As
mentioned earlier, HDX can deliver a high-definition desktop virtualization
user experience to end users over a LAN, WAN, or even over the Internet.
Another fantastic feature of XenDesktop is that it won’t lock you into any
virtual infrastructure. In other words, you may either have Citrix XenServer,
VMware Infrastructure vSphere (4 or 4.1), or Microsoft Hyper-V as your virtual
infrastructure, and it won’t matter. XenDesktop will be able to run on any of
them.
Let’s now have a look at the various components of XenDesktop 5.

Components of XenDesktop 5

Host / Virtual Infrastructure - This refers to
either XenServer, vSphere, or Hyper-V. Note that the virtual infrastructure
won’t be needed all the time. For example, you won’t need a virtual
infrastructure if you stream directly to physical devices.Controller / Desktop Delivery Controller (DDC) -
The DDC is the most important component of XenDesktop. It is the one
responsible for matching a user with an available desktop. When a user connects
to the server, the DDC will be contacted and it will determine which desktop
should be assigned to the user. You may also think of it as a load balancer that
connects users to their appropriate desktops.Provisioning Services (PVS) - This enables
streaming. It allows you to stream complete OS images to physical devices or
even virtual machines, while providing a single centralized managed image. When
needed, applications may also be streamed through this service.Machine Creation Services (MCS) - This is similar
to VMware’s linked clones, wherein you have a master virtual machine with which
you can create snapshots of. These snapshots will then be available for users to
connect to.XenClient - The name of Citrix’s Type-1 Client
Hypervisor. It separates the operating system from the underlying hardware so
that desktop images can be created, secured, deployed and moved across any
supported hardware.

Web Interface (WI) - A web portal that allows users
to login and gain access to all their applications, which can be App-V
applications, Citrix virtualized applications, or entire desktops for that
matter.License Server - A server responsible for keeping
track of all your licenses of the various components in the Citrix
architecture.SSL Gateway - This can either be a physical
appliance, called an Access Gateway, or a virtual applicance, called a
NetsScaler VPX. You can also have a relatively old technology known as the
Secure Gateway.

A typical XenDesktop Architecture

Before we end this article, let me show you a typical XenDesktop
architecture. It may sound quite intimidating at first, but let me assure you
that it’s really simple.
We’ll be discussing these items in more detail on future posts, so let’s just
go through this very briefly.
On the leftmost side, you see two different sets of clients: clients who
connect through your own LAN/WAN and clients from the outside who need to
connect through a DMZ. Those who are required to pass through a DMZ will have to
go through either an Access Gateway, a NetScaler, or a Secure Gateway.
For this particular scenario, we are assuming that both sets of clients will
go through a Web Interface, making it their central connection point.
A user who requests for a VDI will be directed to the DDC. The DDC will then
decide which VM can be connected to the user. When a suitable VM is found, a
direct connection will be established between the user and that VM. In other
words, the DDC will only be needed for initially arranging a connection between
the two.
On the other hand, if a user requests for a published application, then the
Web Interface contacts the XenApp Servers. The XenApp Server containing the
requested app then connects the user with that app.
If you notice, we have an Active Directory on this particular deployment.
That means, user groups, permissions, and other relevant settings on this
deployment will be based off of Active Directory. As mentioned earlier, the
License Server will take charge of the licenses of the components on this
environment.
The SQL Server you see right below the License Server exists to lend support
to both the DDC and the PVS. There’s also a Virtual Infrastructure (either
XenServer, vSphere, or Hyper-V). When needed, the Virtual Infrastructure, will
allow you to share your physical resources of multiple VMs across your entire
infrastructure.
The SAN is not required but you will need it if you have multiple
Provisioning Servers, which will be needing shared disks between them.
Lastly, the File Server to the left of the XenApp Farm exists to hold the
User Profiles. It is where you’ll be saving user personalisations for Office,
Outlook, for user backgrounds, and so on.